Sharif Digital Repository

In Iran, the Iranian Nuclear Waste Management Company (INWMC) is responsible for safe disposal of low-level radioactive waste which results from different processes of nuclear fuel cycle and other radioactive-related activities. The safety assessment program is essential to ensure safe isolation of radioactive waste from the biosphere for long periods of time. Usually, the ground water scenario is considered as the main scenario of radionuclides migration from repository to the biological environment. Thus, it is required to measure the transport parameters of radionuclides in the porous media (soil) around the disposal site. In this research, laboratory scale columns, filled with Nain... 

This research presents an innovative analytical solution to static, free vibration and buckling of an isotropic, homogeneous Mindlin plate with uniform thickness. This method satisfies all classical boundary conditions including free, simply supported and clamped as well as non-classical ones. Moreover, Mindlin plates on Winkler foundation of arbitrary stiffness function are investigated. In this study, the deflection and rotation of straight normal line of the plate about x and y axes are represented as the functions of sine and cosine Fourier series, accompanied by auxiliary functions. These auxiliary functions are of great importance because these functions satisfy arbitrary boundary... 

In the recent years, the world has been faced with a spectacular increase in variety and usage of electronic and electric devices. Unfortunately, the highly increasing march of technology reduces the time of their usage, causing a high degree of electric and electronic waste. Nonetheless, these E-waste enjoys a high percentage in precious metals such as Cadmium, Copper, Nickle, Zinc, Barium, Beryllium, Aluminum, Gold, Silver, Platinum, and so forth. With this in mind, they can be named as “secondary mines”, enjoying higher in degree of these metals even than natural mines. Therefore, extraction and recovery of the very metals are of great importance. Nowadays, using microorganisms in order... 

In this research, the issue of outsourcing control calculations to servers or external computing parties for non-ideal situations has been discussed. Due to the confidentiality of the information of the control systems, it is necessary to guarantee and maintain the privacy of the data from sensors to the actuators. In this research, secure multi-party computation using secret sharing has been utilized to establish the privacy of these data and simultaneously outsource control computing. In other words, the goal is to design a secure controller by means of secure multi-party computations. One of the most important challenges in the design of controllers that use communication channels to send... 

Colon cancer is one of the most common and dangerous cancers, with a high mortality rate. Early diagnosis and accurate prediction of this disease are crucial for effective treatment of patients. This study aims to predict and diagnose colon cancer at an early stage using gene expression data. The main challenges in this field include the high dimensionality of gene expression data, the limited number of samples, and imbalanced data. Previous research has utilized feature selection methods to identify genes associated with colon cancer and applied machine learning algorithms to predict this cancer. In this thesis, we examine a feature selection method that utilizes Kullback-Leibler divergence... 

In this study, various methods of speech time scale modification are inspected and the most important one is modified. First, a brief review on all existing methods for audio time scale modification and its applications is presented in introduction section. As will be noted, the presented method could be classified in three classes of Time domain, Phase-vocoder and signal model. In next chapter a review on Time-domain methods is presented and its advantages and disadvantages have been addressed. Afterward, a review on Phase-vocoder and Signal-model methods is expressed in chapter 3 and 4 respectively. Considering the complexity and extent material relating to these techniques, the research... 

High entropy oxides are a group of oxides which consist of five cations and are stable at high temperature. Since these materials have unique properties such as high ionic media, high capacity and cycle stability, they can be considered for use in lithium-ion batteries. In this regard, in this research, for the first time, the effect of vanadium element in oxide with high entropy for use as anode in lithium-ion battery has been investigated. Therefore, (VCrMnNiCo)3O4 high entropy oxide has been synthesized by hydrothermal method and then the single-phase structure has been stabilized at 900°C. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) studies have... 

We discuss and classify all four dimensional black hole solutions to Einstein-Maxwell-Lambda theory. These solutions contain a black hole region with an event horizon. The cosmological constant can be nonzero and the black hole may possess electric and magnetic charge. We classify solutions according to their asymptotic behavior. Three major parts are asymptotic-flat, asymptotic-de Sitter and asymptotic-Anti-de Sitter and in all of them we discuss Schwarzschild, Reissner-Nordstrom, Kerr and Kerr-Newman black holes separately. Black holes can also have NUT charge and acceleration parameter which make the solution singular in one direction. As a result, these solutions are asymptotically... 

In this study, biosorption of selenium by Pseudomonas putida bacteria was investigated in both single and binary uptake systems. Bacteria cells were immobilized in the chitosan beads, to study impact of microorganism entrapment on the sorption capacity of the fabricated adsorbent. Uptake capacity increased by the entrapped bacterial weight percent up to 20 wt. %; but thereafter, sorption capacity gradually leveled off with an increase in the loading percentage of the bacterial cells.The effects of the three process variables including pH (2-6), biomass dosage (0.5-2.5 g/L) and initial concentration of selenium (50-250 mg/L) on the uptake performance of adsorbent were investigated, and... 

Regarding the increasing trend of network costumers and services, requirement of high-speed and high quality seems to be inevitable. Therefor much effort has been put to issue the problem properly in recent years. Optical fiber networks are attending more attention and optical fiber channels are dominating the world of networking and data. Applying new methods such as CDMA and OFDM raise the issue of maximum achievable rate and quality of these systems.These include the main concentration of this project. First, optical channels are modeled.Then, applying OFDM and CDMA methods, lower and upper bound of channel capacity will be determined  

Design of superconducting material based wide band radiation detectors has recently been attractive. Interesting features of detectors, which are based on Josephson Junctions such as high sensitivity in a wide range of frequencies and low power consumption, potentially have many advantages over other semiconductor-based photo-detectors. According to variety of applications of high-Tc superconductors, particularly YBCO, and significant progress in manufacturing of thin films and Josephson junctions, this thesis mainly focuses on investigation of radiation effects on I-V characteristics of high-Tc step-edge Josephson junctions experimentally. The current-voltage characteristics of fabricated... 

Critical sets and defining sets in combinatorics have been attended by mathematics fans. These subjects have been debated since 1997 and a lot of researches have been done about them and a lot of articles have been published. But number of unsolved questions might be more than answered questions. In these years critical sets for Latin square and defining sets for vertex coloring have been attended and also enough researches about issues related to defining sets for edge coloring and total coloring have not been done. For these reasons we focus on these issues in this thesis. Issues like defining sets for edge coloring and total coloring in complete graphs, generalized Petersen graphs and also... 

Wear is the most important cause of surface damage occurs by direct contact of surfaces. Increasing the quality and strength of surface against different kinds of destructive phenomena is significant in manufacturing of mechanical parts. Surface nanocrystallisation can improve the surface protection against wear and can be done by lazer beam and shot peening. In this investigation by sever shot peening process the surface of A356 Aluminium alloy transforms to nanocrystal structure. The dry sliding wear and friction behaviors of A356 Aluminum were evaluated using a pin-on-disk apparatus at ambient conditions. The stationary diameter of 5mm stainless steel pin produced a wear track (scar) on... 

One of the best ways to overcome the weaknesses of technology services in different industries is right technology transfer with feasibility in the country. 3D painters have been recently widely used industrially in different countries. The 3D printer is one of the new emerging technologies, enabling the production of every 3D objects with any complexity. 3D printing has provided the possibility of producing, in fastest, more economics and regardless of those complexities. By transfer of this kind of technology and proper management, a huge transformation can created in all industries and factories. To do this, there are several technologies of 3D printing, that each of them used in various... 

Nowadays electricity power has a key role in developing various aspects of the world. The great importance of fossil fuel power plants come from their large contribution in electricity power generation. Among the different fossil fuel power generation technologies, supercritical power plants have great advantages. They are an advanced power generation technology with high plant efficiency, high coal utilization and low emission. Their complexity and existing many unavoidable uncertainty sources in their dynamic such as changes of ambient temperature, climate condition and wear of components make their control challenging. To overcome mentioned problems and achieving a good performance, a... 

The relationship between art and philosophy has been disputed for a long time and its history goes back to the ancient Greece. The dominant literary form at that time was poetry or tragedy, which are the first side of this relationship. On the other side was philosophical ethics. Plato and Aristotle are the main protagonists in this quarrel, which is known as the "Ancient Quarrel". I will first examine this quarrel and follow its different forms in the modern era, in which Hegel plays a prominent role by proposing the "end of art" thesis. By examining the criticisms made to this thesis, I will make clear the context in which the contemporary defenses that I explained in the following... 

The most important challenge in microgrids is the coordination of distributed energy resources (DERs), due to the existence of several DERs with fugacious characteristics. Also, energy management in the microgrid is very important because there may be conflicting needs or poor communication between different elements of the microgrid. In this work, a robust frame associated with a quantum version of the Teaching-Learning-Based Optimization (quantum TLBO) algorithm is proposed for the first time to the microgrid optimal energy management problem. Uncertainties in the load and in the output power of renewable energy sources are modeled using robust optimization (RO). The operation cost of the...